Messages in this thread | | | From | Linus Walleij <> | Date | Mon, 25 May 2020 14:08:25 +0200 | Subject | Re: [PATCH] iio: magnetometer: ak8974: Fix runtime PM imbalance on error |
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On Sun, May 24, 2020 at 4:51 AM Dinghao Liu <dinghao.liu@zju.edu.cn> wrote:
> When devm_regmap_init_i2c() returns an error code, a pairing > runtime PM usage counter decrement is needed to keep the > counter balanced. For error paths after ak8974_set_power(), > ak8974_detect() and ak8974_reset(), things are the same. > > However, When iio_triggered_buffer_setup() returns an error > code, we don't need such a decrement because there is already > one before this call. Things are the same for other error paths > after it. > > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
> ak8974->map = devm_regmap_init_i2c(i2c, &ak8974_regmap_config); > if (IS_ERR(ak8974->map)) { > dev_err(&i2c->dev, "failed to allocate register map\n"); > + pm_runtime_put_noidle(&i2c->dev); > + pm_runtime_disable(&i2c->dev); > return PTR_ERR(ak8974->map);
This is correct.
> ret = ak8974_set_power(ak8974, AK8974_PWR_ON); > if (ret) { > dev_err(&i2c->dev, "could not power on\n"); > + pm_runtime_put_noidle(&i2c->dev); > + pm_runtime_disable(&i2c->dev); > goto power_off;
What about just changing this to goto disable_pm;
> ret = ak8974_detect(ak8974); > if (ret) { > dev_err(&i2c->dev, "neither AK8974 nor AMI30x found\n"); > + pm_runtime_put_noidle(&i2c->dev); > + pm_runtime_disable(&i2c->dev); > goto power_off;
goto disable_pm;
> @@ -786,6 +792,8 @@ static int ak8974_probe(struct i2c_client *i2c, > ret = ak8974_reset(ak8974); > if (ret) { > dev_err(&i2c->dev, "AK8974 reset failed\n"); > + pm_runtime_put_noidle(&i2c->dev); > + pm_runtime_disable(&i2c->dev);
goto disable_pm;
> disable_pm: > - pm_runtime_put_noidle(&i2c->dev); > pm_runtime_disable(&i2c->dev); > ak8974_set_power(ak8974, AK8974_PWR_OFF);
Keep the top pm_runtime_put_noidle().
The ak8974_set_power() call is fine, the power on call does not need to happen in balance. Sure it will attempt to write a register but so will the power on call.
Yours, Linus Walleij
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